you will need
3.71 M33: http://www.psp-vault.com/UpDownload-...s-lid-2140.psp
and 3.71 Update file: http://www.psp-vault.com/UpDownload-...t-lid-2123.psp
MAKE SURE YOU KERNEL IS SET TO 3.52
you can do this in recovery mode
start the psp up whilst holding the R shoulder button down,go to configuration find the option for kernel and make sure it’s on 3.52

Installation instructions:



First method for both psp, the prefered when possible:



Requeriments: a fat psp slim with 3.52 M33-3 or 3.52 M33-4. Previous versions of M33 won’t work,

due to a bug that affects them and OE; or a psp slim with 3.60 M33.



- Copy the UPDATE directory into /PSP/GAME/UPDATE and copy the EBOOT.PBP of the 3.71 Sony updater

there but with name "371.PBP". Note: the program will not even show if you copy it to a different folder than that.



- If you are in the fat psp, make sure you have configured the psp to run the game folder in the 3.XX kernel.



- Execute the program, it requires 78% of battery. If you have idstorage corrupted due to a downgrader, the program

will ask you to correct it automatically so the update can continue.



- Press X, and the Sony updater will begin. Sit and enjoy while Sony code installs 3.71 M33



- When finished, the updater will ask you to reboot (pressing X or O). DO IT. Do not skip this step

shutting down the psp by yourself, or you’ll end with a brick.



- You should be now in 3.71 M33

All you need to do now is install the updates
so here we go

installing the 1.50 kernel patch (150 kernel addon 2)
#download the 150 kernel addon 2 from here http://dark-alex.org/
#download the 150 update from here http://dl.qj.net/PSP-Firmware-1.50-F.../163/catid/163
#rename the 150 update eboot to 150.pbp and place it in the root of your memstick
#put the kernel 150 addon 2 update folder in GAME folder on memstick
#scroll to game on xmb and launch the programme
#thats it you now have the 1.50 kernel

installing the 3.71m33-2 update
#download the 3.71m33-2 update here http://dark-alex.org/
#copy the update folder to GAME folder on your memstick
#scroll to game on you xmb and run the programme
#congratulations you are now on 3.71m33-2 enjoy

you will find some people saying 3.71m33-2 is buggy,however this is not true it is as stable as 3.52m33-4 but will not be able to use some plugins because of the new programming from sony but as with any custom firmware programmers are already making plugins compatible for it so enjoy

for installing 3.71m33-2 on slims
universal unbricker
you can get it here http://dark-alex.org/ its called
>> El Despertar del Cementerio v3<< this will install 3.71m33-2 straight to your psp

Installation:

- If you have already a pandora ms, don’t do this part. Otherwise,
format an ms using c+d mspformat or any other tool that allows to move
partition to ~250kb from first sector

Remove ms, usb and connect again usb and ms.
Make PSP and PSP/GAME dirs.

- Copy despertar_cementerio to PSP/GAME/

- Download 1.50, 3.40 and 3.71 update eboots and copy them to ms root with
150.PBP, 340.PBP and 371.PBP names.

- Use the app under a cfw with 2.x or 3.x kernel (be sure that kernel is
selected on recovery to the correct one (2.x or 3.x))

- Once finished, u will have msipl.bin on root. If you already have a pandora
ms, you don’t have to do this step (ipl doesn’t changes lol), otherwise,
use c+d msinst to install ipl on ms; or use dd command from unix, or any
hex-edit program to write on sector 16 on the physical drive.

- Now you can delete 340 and 150 PBP’s, as they won’t be used more; but 371.PBP
will be used for unbricker, so don’t delete it.

- Now you have an universal pandora ms ready to go, and you just need a proper
battery. If you have 1.50 kernel access, use c+d tool. Otherwise, use corly149 tool.

Battery and ms will work on all psp and slims to this date.

Unbricking:

- Press X to install 3.71M33.

- Press O to install original 3.71 (rest of the process as the X option)

- Press [] to dump nand to nand-dump.bin. When done, psp will auto shutdown.

- Press L+R+HOME+start to restore nand from nand-dump.bin

This proccess is very dangerous, and you should *just* use it if it’s your
last chance to get it working.

This is a physical restore process (not a logical one), and will try to make
a 100% exact clon of the dump.

If you are working with a dump that isn’t yours, you will get either a brick
or a corrupt idstorage, depending on the firmware.

If while you are restoring your psp have got any damaged block more than
when you dumped it, you might also get a brick, depending on what block is it.

Works for both PSP and PSP Slim.

themes

the themes for 3.71m33 all go on your memstick and you can change them whenever you want without flashing so this means no chance of a semi brick(yay

you can get themes here http://www.consolespot.net/index.php?network=xmb and here http://www.psp-hacks.com/forums/viewtopic.php?id=113628

installing 3.71 themes (ptf)
#create a folder called THEME inside the PSP folder on your memstick
#copy your desired theme.ptf to the newly created THEME folder on your memstick
#go the setting/theme settings and apply your new theme
#enjoy
make sure the theme is for 3.71